On the market share issue, I have no disagreement with you.
I did, however still prefer the qualities of Kodachrome right through the early 1980s. When the Kodak lab in western Canada closed, that definitely started to wain.
I assume that you weren't in Canada at the end of the 1970s, or bought Kodachrome from outside the country, because as far as I am aware all Canadian sold Kodachrome included processing until the early 1980s.
I was here, born and raised, I got into serious photography in the late 70's and into slides in the early 80's, the Kodachrome I saw shot by friends was not impressive, I used some other chrome films myself, and then gave up on it, when I realized I wasn't going to be projecting them, and printing negatives was cheaper and easier. This is one of the problems a lot of people here are running into, printing from slides now that the successor to Cibachrome, Ilfochrome is history, is only really possible using digital technology.